Dr. Kim D. Janda, a Scripps Research Institute professor, is one of the leading experts, having made addiction vaccines his main priority for the past 25 years. “We view this as an alternative or better way for some people,” he tells The New York Times in reference to rehab programs.

The idea behind the vaccines is to force the body’s immune system to create antibodies against narcotics before they start taking affect, similar to injections for diseases. This means that people already suffering from cocaine addictions, for example, will feel less inclined to pick up the drug again, as the vaccines change the drug’s affects on the body.

“The big problem plaguing these vaccines right now is difficulty predicting in humans how well it’s going to work,” says Janda. Another problem that’s arising is getting the body to recognize cocaine, nicotine and methamphetamine molecules since they are small enough for the immune system to ignore.

Despite these set backs, Janda has had multiple success with both animal and human testing, and the likelihood of reaching a breakthrough in the near future is high.